1. Field of the Invention
The present invention relates generally to the control of the order of data transmission in a two-way communication network which supports various data transmissions having different kinds of quality of service (QoS). More particularly, the present invention is directed to a method for classifying service classes of packet data through an algorithm using several parameters.
2. Description of the Related Art
Modern two-way communication networks that provide for the transmission packet of data have become more and more important because these kinds of networks can make more efficient use of communication resources than conventional communication systems, such as the public switched telephone network (PSTN). For example, the delivery of telephone calls over a two-way network providing for-the transmission packet of data, has become popular due to potential cost savings. In addition, packet data transmission can allow different networks to connect easily to each other through an adapter such as a gateway. As the use of the Internet has dramatically grown, the demand for high speed data transmission has increased so fast that a method to be able to accommodate different networks is needed. In addition, a need exists for a technology to classify service classes provided by a plurality of data networks, such as a computer network, telephone network, or asynchronous transfer mode (ATM) network.
However, conventional two-way communication networks are not designed to classify service classes of packet data. Therefore, each data packet generated from different data sources is processed by using a pure first-in-first-out (FIFO) method at a node that connects the plurality of networks.
A conventional mobile wireless two-way communication network is shown in FIG. 1. Some terminals, such as cellular phone 101, generate real-time packet data corresponding to a voice or video data stream that is time-sensitive, while internet protocol (IP) terminal 102 or personal digital assistant (PDA) 103 generate non-real time packet data that is less time sensitive than a real-time data stream.
Referring to FIG. 1, packet data generated by each terminal 101, 102 and 103 is transmitted to a Base Station Controller (BSC) 106 through a Base Transceiver System (BTS) 105 where each data packet is multiplexed in a FIFO method, and then delivered to the computer network 107 (i.e. the Internet) or public switch telephone network 108 (PSTN) through a router (not shown) that is located in the BTS or BSC. However, a two-way communication network using the FIFO method can cause serious problems such as the late arrival of the data at a destination if the transmission of real-time packet data, such as audio, video, telemetry or control signals, is affected by the congestion of traffic. Furthermore, if the two-way communication network allows for the use of variable packet sizes to transmit or receive the packet data stream, the transmission of real time packet data is more seriously affected.
Presently, there is no way to discriminate whether packet data corresponds to a real time packet data stream or a non-real time packet data stream in conventional two-way communication networks providing for packet data transmission. As a result, the conventional networks are not designed to efficiently handle real time packet stream transmission.